Systems and methods for treating a wastewater stream

Abstract

Provided herein are systems and methods for treating a wastewater stream. In one embodiment, a wastewater stream is treated using a settling tank, a membrane feed tank, and at least one filtration unit.

We claim: 
     
         1 . A wastewater treatment system comprising an external cross-flow ultrafiltration direct membrane filtration (DMF) module including a concentrically baffled concentration tank and a membrane feed tank, the DMF module being configured to up-concentrate influent wastewater and produce a concentrate stream;
 an anaerobic membrane bioreactor (AnMBR) operatively connected to receive the concentrate stream from the DMF module;   wherein the system is configured such that energy produced from biogas generated in the AnMBR offsets at least the total energy demand of the DMF and AnMBR units, including influent heating and system operation, under steady-state conditions.   
     
     
         2 . The system of  claim 1 , wherein the DMF module is operated at a flux and concentration factor selected to maximize energy recovery while maintaining membrane performance and minimizing fouling rates. 
     
     
         3 . The system of  claim 1 , further comprising a heat pump in thermal communication with the AnMBR permeate outlet and the influent line, the heat pump being configured to recover heat from the AnMBR permeate and preheat the influent, thereby reducing the external energy required for influent heating by at least 75 percent compared to direct heating. 
     
     
         4 . The system of  claim 1 , wherein the DMF and AnMBR are integrated such that energy produced from methane at a specified production rate and conversion efficiency offsets both the background energy demand for the treatment system and the energy required for influent heating across a temperature range of 10° C. to 35° C. 
     
     
         5 . The system of  claim 1 , wherein the concentrically baffled concentration tank comprises at least two concentric baffles arranged to direct influent flow radially and tangentially, thereby enhancing solids separation and uniform flow distribution. 
     
     
         6 . The system of  claim 1 , wherein the membrane feed tank includes a variable-speed recirculation pump, the speed of which is controlled by a sensor monitoring influent characteristics. 
     
     
         7 . The system of  claim 1 , wherein the anaerobic membrane bioreactor comprises a gas-liquid-solid separator configured to optimize biogas recovery. 
     
     
         8 . The system of  claim 1 , wherein the DMF module is operated at a transmembrane pressure maintained below 0.5 bar by a pressure control system to minimize membrane fouling. 
     
     
         9 . The system of  claim 1 , wherein the heat pump is configured to recover at least 80 percent of the sensible heat from the AnMBR permeate. 
     
     
         10 . The system of  claim 1 , wherein the system is configured to operate in an energy-neutral mode during periods of low influent temperature or reduced biogas production. 
     
     
         11 . The system of  claim 1 , wherein operational data including cycle durations and sensor readings are continuously logged by a data acquisition system for performance analysis. 
     
     
         12 . The system of  claim 2 , wherein the DMF module is operated at a concentration factor of at least 10. 
     
     
         13 . The system of  claim 3 , wherein the heat pump is activated when the influent temperature falls below a predetermined threshold. 
     
     
         14 . The system of  claim 4 , wherein the integration of the DMF and AnMBR is configured to maintain energy neutrality across a temperature range of 10° to 35° C.